Silver halide emulsions and elements including sensitizers of adamantane structure

ABSTRACT

A photographic silver halide emulsion is disclosed which incorporates from 0.1 to 100 mg per mole of silver of a compound containing six imino groups bonded to four phosphorus, arsenic or antimony atoms. The compound incorporated is of adamantane structure and is useful as a sensitizer for the emulsion alone or in combination with known gold and/or sulfur sensitizers. The compound can be employed in combination with an antifoggant, such as an azaindene. Photographic elements incorporating such emulsions are also disclosed.

United States Patent 1 91 Oftedahl SILVER HALIDE EMULSIONS AND ELEMENTS INCLUDING SENSITIZERS OF ADAMANTANE STRUCTURE [75] Inventor: Edwin N. Oftedahl, Rochester, NY.

[73] Assignee: Eastman Kodak Company,

Rochester, NY.

[22] Filed: July 29, 1974 [2l] Appl. No.: 492,792

[52] US. Cl. 96/107; 96/108; 96/109 [51] Int. CL". 603C [/28 [58] Field of Search 96/109, 108, 107, 29 R [56] References Cited UNITED STATES PATENTS 3,578,449 5/1971 Bloom 96/29 FOREIGN PATENTS OR APPLICATIONS 1,295,463 11/1972 United Kingdom 96/107 195,872 7/1967 U.S.S.R 96/107 1451 Aug. 26, 1975 OTHER PUBLICATIONS Holmes: J. Am. Chem. Soc., Volume 83, pp. 1334-636, March, 1961.

Primary Examiner-Won H. Louie, Jr. Attorney, Agent, or FirmC. 0. Thomas 5 7 ABSTRACT A photographic silver halide emulsion is disclosed which incorporates from 0.1 to 100 mg per mole of silver of a compound containing six imino groups bonded to four phosphorus, arsenic or antimony atoms. The compound incorporated is of adamantane structure and is useful as a sensitizer for the emulsion alone or in combination with known gold and/or sulfur sensitizers. The compound can be employed in combi nation with an antifoggant, such as an azaindene. Photographic elements incorporating such emulsions are also disclosed.

15 Claims, No Drawings SILVER HALIDE EMULSIONS AND ELEMENTS INCLUDING SENSITIZERS ()F ADAMANTANE STRUCTURE My invention relates to silver halide emulsions sensitized with Group VA elements containing imide compounds of adamantane structure and to photographic elements including such emulsions.

The use of compounds containing nitrogen and higher atomic number Group VA elements in combination as scnsitizers for photographic silver halide emulsions and elements is known in the art. For example, British Pat. No. 1,057,949, published Feb. 18, 1967, teaches the sensitization of silver bromide emulsions by developing in the presence of an amido-phosphoric acid polyethylene glycol ester. British Pat. No. 1,295,463, published Nov. 8, I972, teaches that silver halide emulsions can be sensitized through the use of gelatin which has been treated with phosphine. arsine, stibine. white phosphorus or white arsenic or by the direct addition to the emulsion of white phosphorus or white arsenic. Willems et al. U.S. Pat. No. 3,552,968, issued Jan. 5, 1971, teaches sensitization with phosphonitrile trimer and tetramer derivatives.

While varied compounds containing nitrogen and higher atomic weight Group VA elements in combination have been recognized to be sensitizers for photographic silver halide emulsions, it should not be assumed that such compounds are. in general. useful as silver halide sensitizers. Compounds containing nitrogen and higher atomic number Group VA elements. in fact. cover the gamut of performance characteristics. ranging from desensitiyers to sensitizers. Even among such compounds as have been observed to be sensitizers, many have exhibited an ineffectiveness and/or in compatibility with other chemical sensitizers. For example. some of these sensitizers in combination with heavy metal sensitizers. such as gold sensitizers, produce no additional speed increase while others produce prohibitively large increases in fog.

In one aspect then. my invention is directed to a photographic silver halide emulsion improved by the incorporation of a sensitiring amount of a compound containing six imino groups bonded to four atoms of a Group VA element in an adamantane structural arrangement in which the four atoms of the Group VA element each exhibit an atomic number of at least 15.

My invention may be better appreciated by reference to the following description:

The compounds useful as sensitilers in the practice of my invention are those containing six imino groups bonded to four atoms of a Group VA element having an atomic number ofat least l5 and preferably from 15 to 5li.e.. phosphorus. arsenic. antimony. etc. The imino groups can include sterically compatible hydrocarbon substitucnts. such as alkyl. aryl. alkaryl, aralkyl. etc. Typically the hydrocarbon substituents contain ll) (preferably 8) or fewer carbon atoms. The alkyl groups and moieties each preferably incorporate 6 or fewer atoms while the aryl groups and moieties are preferably phenyl groups. The imino groups and Group VA elements are related in an adamantane structure. These compounds are generically designated 2.4.6.8.),[0- hexaaya-l,3.5,7-tctra((iroup \r'A)-adan1antanes, such as 2.4.6.8.).10-hexatva-I.3,5,7-tetraphosphaadamantan es. 2,4.6.8.9, l (l-hcxaazal ,3,5,7-tetraarsaadamantunes, and 2,4.6.8.9,HI-hexaaza-l,3,5,7-tetrastibaadamantanes.

Preferred compounds of this type are those exhibiting the structural formula TABLE I H N N H hexabutyl-Z .4.6.8.9. l -hexaazal .3.5.7- tetrastibadamanatanc hexaphenyl-2.4.6.8 .9. l (Lhexaazal .3 .5.7-tetrastihaadamantane hexahenzyl-2.4.6.8.9. l (l-hexaazzr l .3 .5.7-tetrastibaadamantane hexa-o-tolyl-2.4.6.8.9.1(Lhexaaza-l .3.5.7-tetrastibaadamantane The preparation of adamantane compounds useful in the practice of my invention is generally known in the art. For example. the preparation of compounds ofthis type is taught by Dieter Hass, Z. Anm'g. Allgem. (lie/m. Volume 325. pp. 139-148. March-April. 1963. and Volume 332. pp. 287-298. May-June; H. J. Vetter et al. Z. Aimrg. Allgem. (/zenL. Volume 328. pp. 144453. March-April. 1964; Dieter Hass. 2. (710112., Volume 3. p. 391. October. 1963; and R. R. Ho|mes.J. Am. Chem. 500.. Volume 83. pp. l334l336. March. l96l.

The silver halide emulsions used in accordance with the sensitizers of my invention can comprise. for example. silver chloride. silver bromide, silver hromoiodide. silver chlorobromide. silver chloroiodide. silver chlorohromoiodide and mixtures thereof. The emulsions can be coarse or fine grain emulsions prepared by any of the well-known techniques. e.g.. single jet emulsions. such as those described in Trivelli and Smith. The Pimtugrup/iic Journal. Vol. LXXIX. May. 1939 (pp 330338); double jet emulsions. such as those described in Glatkides. P/IUIQQIU/Ihlt Clicnzislry. Vol. 1. Chapter 28. Fountain Press. London. I958; ammoniacal. thiocyanate or thioether ripened emulsions such as those described in Nietz et al. U.S. Pat. No. 2.222.264. issued Nov. 19. l940; Illingsworth U.S. Pat. No. 3.320.069. issued May l6. I967 and Jones US. Pat. No. 3.574.628. issued Apr. 13. l97l.

The silver halide emulsions utilized in this invention can be surface sensitized and/or internally sensitized. One convenient approach for forming internally sensitized emulsions is to sensitize the grain surfaces of an emulsion to be employed as a core emulsion followed by the further deposition of silver halide on the sensitized surfaces of the grains. Exemplary of internal image forming silver halide emulsions which can be used in the practice of this invention with adamantane sensitizers are those sensitized predominantly on the interior of the silver halide grains as described in Porter et al. U.S. Pat. No. 3.206.3l3. issued Sept. 14. I965; Porter et al. U.S. Pat. No. 3.3l7.322. issued May 2. I967; Spence et al. US. Pat. No. 3.690.89l. issued Sept. 12. 1972; and Evans U.S. Pat. No. 3.761.276. issued Sept. 25. I973.

The silver halide emulsions can be regular grain emulsions such as the type described in Klein and Moisar. J. Pilot. 5111. Vol. 12. No. 5. Sept/Oct l964. pp 242-25] and German Pat. No. 2.l07.ll8. Negative type emulsions can be utilized. as well as direct-positive emulsions as described in lllingsworth US. Pat. No. 3.501.307. issued Mar. 17. I970 and Berriman U.S. Pat. No. 3.367.778. issued Feb. 6. 1968; such cmul sions being surface fogged in addition to being internally sensitized.

Inasmuch as the adamantane sensitizers of my invention produce further enhanced photographic speeds when employed in combination with known chemical sensitizers. silver halide emulsions employed in the practice of my invention are preferably chemically sensitized according to conventional practice in addition to including the adamanlane sensitirers. My silver halide emulsions can be usefully sensitized with chemical sensitizcrs. such as with sulfur. selenium or tellurium compounds; gold. platinum or palladium compounds; or combinations of these. Procedures for chemically sensitizing silver halide emulsions are described in Sheppard et al US. Pat. No. l.b23.499. issued Apr. l5. 1927; Waller et al. US. Pat. No. 2.399.083. issued Apr. 23. 1946'. McVeigh US. Pat. No. 3.297.447. issucd Jan. 10. I967. and Dunn US. Pat. No. 3.297.446. issued Jan. 10. 1967.

My adamantane sensitizers can be added in a variety of ways to photographic emulsions and at various stages in the preparation thereof; however. I prefer to introduce the adamantanc sensitizers of my invention immediately after chemical sensitization by conventional techniques has been completed and before other addenda have been incorporated into the emulsion. The sensitizers can be added with useful effects at the completion of Ostwald ripening and prior to one or more of the final digestion operations. The sensitizers are preferably added to the silver halide emulsion after the silver halide grains are substantially in their final size and shape. The adamantane sensitizers can be added in methanol. acetone or other innocuous organic solvents. To avoid thermally degrading the adamantane sensitizers it is generally preferred that the silver halide emulsion not be maintained above a temperature of about 50 to 60C for an extended period in preparation steps subsequent to adamantane incorporation. Ef-

fective adamantane sensitization can be obtained by holding the emulsion at an elevated temperature of up to about 40C. or more for a period ranging from a few minutes to an hour or morepreferably 10 to 40 minutes.

Any sensitizing amount of the adamantane compounds of this invention can be usefully incorporated into the silver halide emulsion. Typically concentrations of from about 0.] to 100 mg of adamantane sensitizer per mole of silver halide. preferably 0.5 to 50 mg of adamantane sensitizer per mole of silver halide. can be employed.

Since higher concentrations of the adamantane sensi tizers can raise fog levels, the maximium concentrations of the adamantane sensitizers is a function of (a) the amount of background fog compatible with the particular photographic application and (b) whether or not an antifoggant is incorporated in the silver halide emulsion. While the adamantane sensitizers are generally compatible with known antifoggants and stabilizers. l have found the adamantane sensitizers employed in the practice of this invention to be particularly effective in combination with known azaindene antifoggants. most preferably tetrazaindene antifoggants. Exemplary antifoggants and stabilizers. each used alone or in combination include the following:

a. thiazolium salts described in Brooker et al. US. Pat. No. 2.131.038. issued Sept. 27. l938 and Allen ct al. US. Pat. No. 2.694.7l6. issued Nov. in. 1954'.

b. the azaindcnes described in Piper US. Pat. No. 2.886.437. issued May I2. 1959 and Heimbach ct al. US. Pat. No. 2.444.605. issued July 6. l948;

c. the mercury salts as described in Allen ct al. US. Pat. No. 2.728.663. issued Dec. 27. 1955;

L. the uramles described in Anderson ct al. US. Pat. No. 3.2b7.l35. issued Nov. 22. 1966;

e. the sulfocatcchols described in Kcnnard ct al. US. Pat. No. 3.236.652. issued Feb. 22. 1966;

f. the oximes described in Carroll ct all British Pat. No. 623.448. issued May 18. 1949;

g. nitron;

h. nitroindazoles;

(ill

i. mcrcaptotetrazoles described in Kendall ct al. US. Pat. No. 2.403.927. issued July l6. 1946; Kcnnard ct al. US. Pat. No. 3.266.897. issued Aug. lb. 1966; and Luckey ct al. US. Pat. No. 3.397.987. issued Aug. 20. 1968:

j. the polyvalcnt metal salts described in .lones US. Pat. No. 2.839.405. issued June l7. 1958;

k. the thiuronium salts described in Herz ct al. US. Pat. No. 3.220.839. issued Nov. 30. 1965; and

l. the palladium. platinum and gold salts described in Trivelli et al. US. Pat. No. 2.566.263. issued Aug. 28. I]; and Yutzy et al. US. Pat. No. 2.597.9l5. issued May 27. 1952.

In addition to the components above mentioned the silver halide emulsions include a vehicle for dispersing the silver halide grains. The vehicle is typically a hydrophilic colloid. such as gelatin. but can take any conventional form. In addition. the silver halide emulsion can contain any one or a variety of conventional photographic emulsion addenda, such as hardeners. spectral sensitizers. brighteners. coating aids. plasticizers and lubricants. absorbing and filter dyes. developing agents. development modifiers. etc. Typical conventional vehicles and addenda of this type useful in the practice of this invention are disclosed in Product Licensing Index. Vol. 92. December l97l. publication 9232. pages l07 through 1 10. here incorporated by reference.

The photographic emulsions according to my invention can be employed as coatings in single and multilayer photographic clemcnts. Such elements typically include a conventional photographic support of the type disclosed specifically in paragraph X of Product Lit-easing Index. cited above. The photographic emulsion layers can be employed in combination with sub bing. interlayers, Carey Lea silver layers. antihalation layers. etc.. as is well understood in the art.

The photographic elements according to my inven tion can be applied to a variety of applications. The photographic elements can be used with X-rays or can be orthochromatic. panchromatic or infrared sensitive. The photographic elements can be employed to form black-and-white images or to form colored or multicolored images in one or a plurality of layers as taught specifically in paragraph XXll of Product Licensing In- (1m. cited above. The photographic elements can be of a type which form images upon development in con ventional silver halide developing solutions, which form images by dry physical development. which form images by image transfer. etc. The photographic elements can be employed as lithographic printing plates as taught in paragraph XXIV of Pruu'ucr Licensing 1ne/m'. cited above. The photographic elements can be formed to produce positive or negative images and can be formed to be of the direct print type. as specifically disclosed in paragraph XXV of Product Licensing Inr/m. cited above.

The following examples are intended to futhcr illustrate my invention.

EXAMPLE I A silver bromide emulsion having a mean grain size of0.4 micron in diameter was prepared using a conventional double iet technique. To the emulsion were added a conventional spreading agent. hardening agent and antifoggant. thc antifoggant being 4-hydroxy-bmethyl-l .3.3a.7-tctra7aindcnc. l'hc emulsion was separated into equal portions and chemically sensitized to a maximum obtainable speed using the reduction sensitiyiers in the concentrations set forth below in Table II. The emulsion samples \vere then coated on a film support at 29 mg silver per square decimeter. exposed. developed for 4 minutes in Kodak Developer D- l 9 (the composition of which is set forth at page 43 of Kodak Advanced Data Book J-l titled Processing Chemicals and Formulas for BIack and-Whitc Photography. (1th edition. published i963). fixed. washed and dried.

TABLE II Reduction (once-titration Fresh Sensitiver mg Sens/mole Ag Relatbc Speed Fo None None ltttl (MIR thiourea Llit1\itit. 2.tt It; out 2 it: J'J'r' [Hi4 Table ll shows hexamethyl-2.4.6.8.9. lU-hexaaza- Example 1 was repeated. except that no antii'oggant adamantane sensitizer to more than double the emulsion speed when combined with the sulfur sensitizer as compared with the speed obtainable with the adamantane senstizier alone and to produce a relative speed increase of more than 5 times as compared to the emulsion containing the sulfur sensitizer alone. The combination of the adamantane sensitizer. the sulfur sensitizer and the gold sensitizer produces an emulsion hav ing a relative speed more than 17 times greater than that of the unsensitized emulsion, more than i 1 times greater than that of the sulfur sensitized emulsion. more than 6 times greater than that of sulfur and gold sensitized emulsion and more than twice that of the adamantane and sulfur sensitized emulsion. Further. Table III shows that the adamant-me sensitizer does not increase fog levels in combination with gold and/or sulfur sensitizers.

EXAMPLES 3 THROUGH 5 The procedure of Example 2 was repeated. except that the mean diameter of the silver bromide grains was 0.2 micron and the sensitizers and sensitizer combinations and concentrations were employed as set forth below in Table IV.

Table IV shows that the adamantane sensitizer is more effective than the sulfur sensitizer or a combination of the sulfur sensitizer and the gold sensitizer. even though the adamantane sensitizer is employed in a much lower concentration. Table I" further shows the TABLE IV Reduction Coneentrationt sl Fresh Scnsiti7er mg Sens/mole Ag Relative Speed Fog None None 65 (L03 9. 95 (1.04

33 6.6 tresp.) l7-1 (MM 0.! 234 (to-t r 5H. t!.l '-).ll tresp.| Stll (HI-1 o su o U l 33 (1.0 tresp.) LI-JH till-4 was incorporated and the scnsitizers and concentrations were employed as set forth below in Table Ill.

TABLE III Reduction ('onccntralion fresh Senstti/er mg Scnstmolc Ag Relative Speed Fu None None lllll (HI-1 ll'lfltllklliil ;|l1ilt]t lpl1|i It] 257 ll ()4 phtnc 5-: it. NF] llll-l (ill The invention has been described with particular reference to preferred embodiments thereof but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

I claim:

1. In a photographic silver halide emulsion the improvement comprising the incorporation of a sensitizing amount of a compound of the structural formula wherein.

Z represents a Group VA element having an atomic number of from at least l5 inclusive and R is hydrogen or a hydrocarbon containing 8 or fewer carbon atoms.

2. In a photographic silver halide emulsion according to claim 1, the further improvement in which said emulsion is additionally sensitized with a gold sensitizer. a sulfur sensitizer or a combination of gold and sulfur sensitizers.

3. in a photographic silver halide emulsion according to claim 2, the further improvement in which said emulsion contains an azaindene antifoggant.

4. In a photographic silver halide emulsion according to claim 3, the further improvement in which said emulsion contains a tetraiaindene antifoggant.

5. In a photographic silver halide emulsion the improvement comprising the incorporation of a sensitizing amount of a compound of the structural formula wherein,

Z represents a Group VA element having an atomic number of from l5 to SI inclusive and R is hydrogen or a hydrocarbon containing 8 or fewer carbon atoms.

6. in a photographic silver halide emulsion according to claim 5. the further improvement in which said Group VA element is phosphorus.

7. In a photographic silver halide emulsion according to claim 6. the further improvement in which R is an alkyl group having 8 or fewer carbon atoms.

8. In a photographic silver halide emulsion. the improvement comprising the incorporation of a sensitizing amount of a compound having the structural formula 9. In a photographic silver halide emulsion. according to claim 8, the further improvement in which said emulsion is additionally sensitized with a gold sensitizer. a sulfur sensitizer or a combination of gold and sulfur sensitizers.

[0. In a photographic silver halide emulsion according to claim 9, the further improvement in which said emulsion contains an azaindene antifoggant.

I]. In a photographic element comprised of a support and. as a coating thereon. a photographic silver halide emulsion layer, the improvement in which said emulsion is as set forth in claim l.

12. In a photographic element according to claim 11, the further improvement in which said emulsion includes gold sensitizing means. sulfur sensitizing means. or a combination of gold and sulfur sensitizing means.

[3. in a photographic element according to claim [2, the further improvement in which said emulsion includes antifoggant means [4. in a photographic element according to claim 1], the further improvement in which said emulsion includes a phosphorus imide sensitizer.

15. In a photographic element comprised of a support and. a coating thereon. a photographic silver halide emulsion layer. the improvement in which said photographic silver halide emulsion includes a sensitizing amount of hexamethyl-2,4.6.8,9.lU-

hexaazal .3.5,7-tetraphosphaadamantane.

gold sensitizing means. sulfur sensitizing means or a combination of gold and sulfur sensitizing means. and

azaindene antifoggant means. 

1. IN A PHOTOGRAPHIC SILVER HALIDE EMULSION THE IMPROVEMENT COMPRISING THE INCORPORATION OF A SENSITIZING AMOUNT OF A COMPOUND OF THE STRUCTURAL FORMULA
 2. In a photographic silver halide emulsion according to claim 1, the further improvement in which said emulsion is additionally sensitized with a gold sensitizer, a sulfur sensitizer or a combination of gold and sulfur sensitizers.
 3. In a photographic silver halide emulsion according to claim 2, the further improvement in which said emulsion contains an azaindene antifoggant.
 4. In a photographic silver halide emulsion according to claim 3, the further improvement in which said emulsion contains a tetrazaindene antifoggant.
 5. In a photographic silver halide emulsion the improvement comprising the incorporation of a sensitizing amount of a compound of the structural formula
 6. In a photographic silver halide emulsion according to claim 5, the further improvement in which said Group VA element is phosphorus.
 7. In a photographic silver halide emulsion according to claim 6, the further improvement in which R is an alkyl group having 8 or fewer carbon atoms.
 8. In a photographic silver halide emulsion, the improvement comprising the incorporation of a sensitizing amount of a compound having the structural formula
 9. In a photographic silver halide emulsion, according to claim 8, the further improvement in which said emulsion is additionally sensitized with a gold sensitizer, a sulfur sensitizer or a combination of gold and sulfur sensitizers.
 10. In a photographic silver halide emulsion according to claim 9, the further improvement in which said emulsion contains an azaindene antifoggant.
 11. In a photographic element comprised of a support and, as a coating thereon, a photographic silver halide emulsion layer, the improvement in which said emulsion is as set forth in claim
 1. 12. In a photographic element according to claim 11, the further improvement in which said emulsion includes gold sensitizing means, sulfur sensitizing means, or a combination of gold and sulfur sensitizing means.
 13. In a photographic element according to claim 12, the further improvemEnt in which said emulsion includes antifoggant means.
 14. In a photographic element according to claim 11, the further improvement in which said emulsion includes a phosphorus imide sensitizer.
 15. In a photographic element comprised of a support and, as a coating thereon, a photographic silver halide emulsion layer, the improvement in which said photographic silver halide emulsion includes a sensitizing amount of hexamethyl-2,4,6,8,9,10-hexaaza-1,3,5,7-tetraphosphaadamantane, gold sensitizing means, sulfur sensitizing means or a combination of gold and sulfur sensitizing means, and azaindene antifoggant means. 